Melissa P. Knauert

Sleep and Sleep Disordered Breathing in Hospitalized Patients

Sleep is a fundamental physiological process necessary for recovery from acute illness. Unfortunately for hospitalized patients, sleep is often short, fragmented, and poor in quality, and may be associated with adverse outcomes including inpatient delirium. Many factors contribute to poor sleep in the hospital setting, including preexisting sleep deprivation, sleep disordered breathing, environmental noise and light, patient care activities, and medications. Sleep disordered breathing increases the risk of potentially life-threatening cardiovascular, respiratory, and metabolic consequences, and therefore should be diagnosed and treated in hospitalized patients. Mitigating the sequelae associated with poor sleep quality and sleep disordered breathing requires early identification of modifiable factors impacting a patients sleep, including engagement of a multidisciplinary team. In this article, we review the current knowledge of sleep in hospitalized patients with a detailed focus on patients with sleep disordered breathing.

Feasibility study of unattended polysomnography in medical intensive care unit patients

OBJECTIVES To evaluate the feasibility of using unattended, portable polysomnography (PSG) to measure sleep among patients in the medical intensive care unit (MICU). BACKGROUND Accurate measurement of sleep is critical to studies of MICU sleep deprivation. Although PSG is the gold standard, there is limited data regarding the feasibility of utilizing unattended, portable PSG modalities in the MICU. METHODS MICU based observational pilot study. We conducted unattended, 24-h PSG studies in 29 patients. Indicators of feasibility included attainment of electroencephalography data sufficient to determine sleep stage, sleep efficiency, and arousal indices. RESULTS Electroencephalography data were not affected by electrical interference and were of interpretable quality in 27/29 (93%) of patients. Overnight sleep efficiency was 48% reflecting a mean overnight sleep duration of 3.7 h. CONCLUSIONS Unattended, portable PSG produces high quality sleep data in the MICU and can facilitate investigation of sleep deprivation among critically ill patients. Patient sleep was short and highly fragmented.

Clinical consequences and economic costs of untreated obstructive sleep apnea syndrome

Objective To provide an overview of the healthcare and societal consequences and costs of untreated obstructive sleep apnea syndrome. Data sources PubMed database for English-language studies with no start date restrictions and with an end date of September 2014. Methods A comprehensive literature review was performed to identify all studies that discussed the physiologic, clinical and societal consequences of obstructive sleep apnea syndrome as well as the costs associated with these consequences. There were 106 studies that formed the basis of this analysis. Conclusions Undiagnosed and untreated obstructive sleep apnea syndrome can lead to abnormal physiology that can have serious implications including increased cardiovascular disease, stroke, metabolic disease, excessive daytime sleepiness, work-place errors, traffic accidents and death. These consequences result in significant economic burden. Both, the health and societal consequences and their costs can be decreased with identification and treatment of sleep apnea. Implications for practice Treatment of obstructive sleep apnea syndrome, despite its consequences, is limited by lack of diagnosis, poor patient acceptance, lack of access to effective therapies, and lack of a variety of effective therapies. Newer modes of therapy that are effective, cost efficient and more accepted by patients need to be developed.

Therapeutic Applications of Carbon Monoxide

Heme oxygenase-1 (HO-1) is a regulated enzyme induced in multiple stress states. Carbon monoxide (CO) is a product of HO catalysis of heme. In many circumstances, CO appears to functionally replace HO-1, and CO is known to have endogenous anti-inflammatory, anti-apoptotic, and antiproliferative effects. CO is well studied in anoxia-reoxygenation and ischemia-reperfusion models and has advanced to phase II trials for treatment of several clinical entities. In alternative injury models, laboratories have used sepsis, acute lung injury, and systemic inflammatory challenges to assess the ability of CO to rescue cells, organs, and organisms. Hopefully, the research supporting the protective effects of CO in animal models will translate into therapeutic benefits for patients. Preclinical studies of CO are now moving towards more complex damage models that reflect polymicrobial sepsis or two-step injuries, such as sepsis complicated by acute respiratory distress syndrome. Furthermore, co-treatment and post-treatment with CO are being explored in which the insult occurs before there is an opportunity to intervene therapeutically. The aim of this review is to discuss the potential therapeutic implications of CO with a focus on lung injury and sepsis-related models.

Sleep Loss and Circadian Rhythm Disruption in the Intensive Care Unit

Critical illness is associated with profound sleep disruption. Causality is diverse and includes physiologic, psychological, and environmental factors. There are limited pharmacologic interventions available to treat sleep disturbances in critical illness; however, multidisciplinary strategies that alter the intensive care unit (ICU) environment and cluster care delivery have shown promise in sleep and circadian promotion and delirium reduction. With the appropriate administrative support and involvement of diverse ICU stakeholders, effective strategies could be created, implemented, and maintained to improve sleep disruption in critically ill patients.

Sleep Disturbance after Hospitalization and Critical Illness: A Systematic Review

Rationale: Sleep disturbance during intensive care unit (ICU) admission is common and severe. Sleep disturbance has been observed in survivors of critical illness even after transfer out of the ICU. Not only is sleep important to overall health and well being, but patients after critical illness are also in a physiologically vulnerable state. Understanding how sleep disturbance impacts recovery from critical illness after hospital discharge is therefore clinically meaningful. Objectives: This Systematic Review aimed to summarize studies that identify the prevalence of and risk factors for sleep disturbance after hospital discharge for critical illness survivors. Data Sources: PubMed (January 4, 2017), MEDLINE (January 4, 2017), and EMBASE (February 1, 2017). Data Extraction: Databases were searched for studies of critically ill adult patients after hospital discharge, with sleep disturbance measured as a primary outcome by standardized questionnaire or objective measurement tools. From each relevant study, we extracted prevalence and severity of sleep disturbance at each time point, objective sleep parameters (such as total sleep time, sleep efficiency, and arousal index), and risk factors for sleep disturbance. Synthesis: A total of 22 studies were identified, with assessment tools including subjective questionnaires, polysomnography, and actigraphy. Subjective questionnaire studies reveal a 50‐66.7% (within 1 mo), 34‐64.3% (>1‐3 mo), 22‐57% (>3‐6 mo), and 10‐61% (>6 mo) prevalence of abnormal sleep after hospital discharge after critical illness. Of the studies assessing multiple time points, four of five questionnaire studies and five of five polysomnography studies show improved aspects of sleep over time. Risk factors for poor sleep varied, but prehospital factors (chronic comorbidity, pre‐existing sleep abnormality) and in‐hospital factors (severity of acute illness, in‐hospital sleep disturbance, pain medication use, and ICU acute stress symptoms) may play a role. Sleep disturbance was frequently associated with postdischarge psychological comorbidities and impaired quality of life. Conclusions: Sleep disturbance is common in critically ill patients up to 12 months after hospital discharge. Both subjective and objective studies, however, suggest that sleep disturbance improves over time. More research is needed to understand and optimize sleep in recovery from critical illness.

Factors Influencing Patients’ Sleep in the Intensive Care Unit: Perceptions of Patients and Clinical Staff

Background Multiple factors are believed to contribute to disruption of patients’ sleep and negatively affect clinical outcomes in the intensive care unit. Achieving restorative sleep for critically ill patients remains a challenge. Objectives To explore the perceptions and beliefs of staff, patients, and surrogates regarding the environmental and nonenvironmental factors in the medical intensive care unit that affect patients’ sleep. Methods This qualitative study included 24 medical intensive care unit staff (7 physicians, 5 respiratory therapists, 10 nurses, and 2 patient‐care assistants), 8 patients, and 6 patient surrogates. Semistructured interviews were conducted, and qualitative analysis of content was used to code, categorize, and identify interview themes. Results Interview responses revealed 4 themes with related subthemes: (1) The overnight medical intensive care unit environment does affect sleep, (2) nonenvironmental factors such as difficult emotions and anxiety also affect sleep, (3) respondents’ perceptions about sleep quality in the medical intensive care unit were highly variable, and (4) suggestions for sleep improvement included reassuring patients and care‐clustering strategies. Conclusions Results of this study suggest that environment is not the only factor influencing patients’ sleep. Decreases in environmental sources of disturbance are necessary but not sufficient for sleep improvement. Guideline‐recommended clustered care is needed to provide adequate sleep opportunity, but patients’ emotions and anxiety also must be addressed.

Comparing average levels and peak occurrence of overnight sound in the medical intensive care unit on A-weighted and C-weighted decibel scales

PURPOSE Sound levels in the intensive care unit (ICU) are universally elevated and are believed to contribute to sleep and circadian disruption. The purpose of this study is to compare overnight ICU sound levels and peak occurrence on A- vs C-weighted scales. MATERIALS AND METHODS This was a prospective observational study of overnight sound levels in 59 medical ICU patient rooms. Sound level was recorded every 10 seconds on A- and C-weighted decibel scales. Equivalent sound level (Leq) and sound peaks were reported for full and partial night periods. RESULTS The overnight A-weighted Leq of 53.6 dBA was well above World Health Organization recommendations; overnight C-weighted Leq was 63.1 dBC (no World Health Organization recommendations). Peak sound occurrence ranged from 1.8 to 23.3 times per hour. Illness severity, mechanical ventilation, and delirium were not associated with Leq or peak occurrence. Equivalent sound level and peak measures for A- and C-weighted decibel scales were significantly different from each other. CONCLUSIONS Sound levels in the medical ICU are high throughout the night. Patient factors were not associated with Leq or peak occurrence. Significant discordance between A- and C-weighted values suggests that low-frequency sound is a meaningful factor in the medical ICU environment.

Creating Naptime: An Overnight, Nonpharmacologic Intensive Care Unit Sleep Promotion Protocol

Introduction: Patients in the intensive care unit (ICU) have significantly disrupted sleep. Sleep disruption is believed to contribute to ICU delirium, and ICU delirium is associated with increased mortality. Experts recommend sleep promotion as a means of preventing or shortening the duration of delirium. ICU Sleep promotion protocols are highly complex and difficult to implement. Our objective is to describe the development, pilot implementation, and revision of a medical ICU sleep promotion protocol. Methods: Naptime is a clustered-care intervention that provides a rest period between 00:00 and 04:00. We used literature review, medical chart review, and stakeholder interviews to identify sources of overnight patient disturbance. With stakeholder input, we developed an initial protocol that we piloted on a small scale. Then, using protocol monitoring and stakeholder feedback, we revised Naptime and adapted it for unitwide implementation. Results: We identified sound, patient care, and patient anxiety as important sources of overnight disturbance. The pilot protocol altered the timing of routine care with a focus on medications and laboratory draws. During the pilot, there were frequent protocol violations for laboratory draws and for urgent care. Stakeholder feedback supported revision of the protocol with a focus on providing 60- to 120-minute rest periods interrupted by brief clusters of care between 00:00 and 04:00. Discussion: Four-hour blocks of rest may not be possible for all medical ICU patients, but interruptions can be minimized to a significant degree. Involvement of all stakeholders and frequent protocol reevaluation are needed for successful adoption of an overnight rest period.

Association between death and loss of stage N2 sleep features among critically Ill patients with delirium

Purpose: Critically ill patients experience significant sleep disruption. In this study of ICU patients with delirium, we evaluated associations between the loss of stage N2 features (K‐complexes, sleep spindles), grade of encephalopathy based on electroencephalography (EEG), and intensive care unit (ICU) outcomes. We hypothesized that loss of stage N2 features is associated with more severe grades of encephalopathy and worse ICU outcomes including death. Materials and methods: This was an observational cohort study of 93 medical ICU patients without primary acute brain injury who underwent continuous EEG. Type and severity of critical illness, sedative‐hypnotic use, length of stay, modified Rankin Scale at hospital discharge, and death during hospitalization were abstracted from the medical record. EEG was evaluated for grade of encephalopathy and sleep features. Results: Patients without K‐complexes or without sleep spindles had more severe encephalopathy and higher odds of death. The odds ratio for patients without K‐complexes was 18.8 (p = .046). The odds ratio for patients without sleep spindles was 6.3 (p = .036). Conclusions: Loss of stage N2 features is common and associated with more severe encephalopathy and higher odds of death. The absence of either Stage N2 feature, K complexes or sleep spindles, may have important prognostic value.